While the magnitude of VTE increases dramatically with advancing age, relatively little is known about the natural history of this disorder in the elderly, particularly with respect to its impact on quality of life (QOL) and functional capacity. The high-risk elderly population has generally been underrepresented in clinical trials evaluating therapeutic options for this condition, thereby leaving clinicians to generalize resulting data to the elderly when making clinical decisions. The goals of the proposed multicenter observational study are to systematically characterize the contemporary clinical course and characteristics of VTE in the elderly, use of different management practices, associated morbidity (e.g. VTE recurrence, post-thrombotic syndrome, bleeding) and mortality, and measures of general and disease specific QOL. To address these and related issues, we propose to carry out a cohort study of approximately 860 elderly male and female patients diagnosed with VTE at 4 city of Worcester (MA) and 5 city of Hamilton (Ontario) hospitals over a 27 month period in 2008 to 2010. Baseline information about patient's demographic and clinical characteristics as well as diagnostic and acute therapeutic interventions will be abstracted from medical records and collected during an initial in-person interview. Follow-up of cohort enrollees will be conducted through telephone contact as well as through the review of hospital and ambulatory care records at 3, 6, and then every 6 months for a maximum follow-up period of up to 3 years. We will also conduct a retrospective review the medical records of all elderly subjects diagnosed with VTE at participating Worcester and Hamilton hospitals between 2008 and 2010. The availability of data from both patient sources will provide a comprehensive picture of the demographic, clinical, acute treatment characteristics and limited outcomes (recurrent VTE and death) of elderly subjects with VTE in these two communities (estimated overall sample size of1400 subjects). Lay summary: This study will evaluate the impact of venous thromboembolism (blood clots of the legs and lungs) on elderly patients'subsequent health and quality of life. We will also examine how elderly patients with venous thromboembolism are currently being treated, whether some patients are at risk for inappropriate or under treatment, and the relationship of treatment to future complications.